Scrambling and encryption of broadcast signals to prevent unauthorized listening or viewing of audio and video programs is a well known technique in the art of pay-per-view services. In the case of cable or satellite television transmissions, a set-top box is programmed by the broadcasting service to descramble or decipher channels which are subscribed to, and paid for, by a user. When a user desires to access a pay-per-view service, such as a pay-per-view movie, one method requires the user to call up the service provider to order the movie. The user receives an authorization code to enter manually into the set-top box. If the user waits until the start of the movie before calling for an authorization code, the user will miss the beginning of the movie.
Smart cards, also known as prepaid transaction cards, have been used in various business sectors to prepay for services, such as long distance telephone service, photocopy machines, and train transportation. A card equipped with a magnetic or electronic recording medium, such a magnetic strip or a memory chip, is sold to a user. Monetary value is encoded on the cards' recording medium, the amount of which is determined by the user within limits set by the service provider. For example, when a smart card is used for daily commuting on a local rail system, the maximum monetary value which can be placed on the card may be limited by the amount of currency that will be accepted by the card vending machine. The amount that a smart card can have at any one time may also be limited for security reasons, since the card is not limited to use by any one person and is simply a means to convert legal tender to a more convenient electronic form.
Electronic transfer of digital information to a user is described in U.S. Pat. No. 5,845,262. A user selects information to be retrieved, and inserts a prepaid card into an information vending machine. The vending machine deducts an amount needed to pay for the selected information, and records the purchased information onto a recording medium, which can be the smart card, an IC card, a floppy disk, and the like. The information is transferred to the user in a readily readable format.
Dissemination and sale of a digital product using personal computers is described in U.S. Pat. No. 5,898,777. An encrypted digital product, such as software, is downloaded to a user computer. A purchaser triggers a purchase, using unencrypted purchasing software provided with the encrypted product, between the personal computer and a bank network. The merchant receives credit for the purchase from the banking network, and the encrypted product is deciphered by the purchasing program. In this manner the merchant does not have to deal with giving the user cumbersome decipher keys to enter manually.